progress-bar: issue Windows Terminal progress indicating ANSI sequences

progress-bar: issue Windows Terminal progress indicating ANSI sequences

This generates the Windows Terminal OSC sequences indicating progress.
This let's the terminal know that we are doing a slow operation, and how
we are progressing.

Windows Terminal uses this in two ways: it shows a circle in the tab
that completes, and it highlights the progress in the task bar.

I found no Linux terminal that currently supports it, but also none that
didn't like it. Thankfully most terminals correctly ignore unrecognized
OSC sequences.

I think we should just merge this, and see if this trips up too many
people, but I have reason to believe this shouldn't be too bad.

And yes, I do work from Windows Terminal sometimes, ssh into my Linux
build systems, and it is really cute seeing the progress animation
there.